Over the next few decades, the world’s population will be older on average than it’s ever been before.

Brazil’s senior population is expected to grow to 30% of the total population in 2030 from just 10% in 2014. A quarter of Europe’s population will be above 65 by 2030, and Japan’s 65-plus population will climb to 38% in 2055.

#-ad_banner-#In 15 years, China will have an estimated 340 million people over the age of 60. That’s nearly four times larger than the United States’ projected 92 million senior citizens.

People all over the world are living longer than they did 50 years ago, and the growing global senior population is driving a steady wave of demand for drugs and medicine.

Pharmaceutical industry research firm EvaluatePharma recently projected global pharma sales at $1.107 trillion in 2020, up from $750 billion in 2014.

The best-selling drugs will treat chronic illnesses and diseases more prevalent in the elderly such as cancer, cardiovascular disease, dementia and Alzheimer’s.

U.S. drug companies, like Pfizer (NYSE: PFE), will benefit from this trend, but I expect foreign-based companies to benefit more because they derive a larger percentage of their revenue from international markets.

And this happens to be the perfect time to buy international drug stocks.

For one, global pharma stocks are on sale compared with those in the United States.

The forward price-to-earnings (P/E) ratio for iShares Global Healthcare (NYSE: IXJ) is 22. That’s a 15% discount to iShares U.S. Pharmaceuticals’ (NYSE: IHE) forward P/E ratio of 26.

Digging into individual stocks reveals even better valuations.

Current High-Yield International portfolio holding GlaxoSmithKline (NYSE: GSK), one of the world’s largest vaccine manufacturers, has a forward P/E ratio of just 17. My portfolio’s other healthcare holding, Sanofi (NYSE: SNY), the world’s No. 1 diabetes treatment maker, has a forward P/E ratio of just 16.

Global pharma stocks also offer better yields than their U.S. counterparts.

IXJ’s dividend yield of 1.5% doesn’t exactly jump off the page, but it’s still a 67% premium to IHE’s 0.9% dividend yield.

Glaxo’s current yield of 5.8% is a 81% premium to U.S.-based Pfizer’s 3.2% yield. It also ranks higher than 97% of its industry peers.

It’s unusual for international drug stocks to be trading with these relatively low P/E ratios and outsized yields. However, I don’t expect that to last long.

2014 was a great year for drug approvals in the United States and Europe. The Federal Drug Administration approved 41 novel medications, 14 more than in 2013 and approaching the all-time high of 53 in 1996. The European Medicines Agency recommended 82 new drugs, up from 79 in 2013 and 57 in 2012.

My portfolio holdings were in on the action. Glaxo and Sanofi scored one FDA approval each in 2014.

This is a strong signal that years of hard work and billions in research and development will help the global pharma industry and its best companies return to revenue growth in the next 12-to-24 months.

That’s why I recently added another global leader in pharmaceuticals to my High-Yield International portfolio.

This company led the entire pharmaceutical industry in 2014 with four FDA approvals. It is already cashing in on high-growth markets in China and the rest of Asia, and offers a current yield of 5.6%. Shares are undervalued, with a P/E ratio below the industry average. This company also looks like a strong buyout target, as it was almost purchased in 2014 for $110 billion.

If you’d like to learn more about the best way to benefit from the aging world’s need for medicine and the other trends leading to profitable investments and sky-high yields across the globe, check out my latest report here.